Details on the load cell types and truck scale accessories

Design and capacity of a weighbridge.

The structural integrity of the weighbridge is the most important factor to consider when purchasing a semi truck scales. A failing weighbridge causes ongoing issues that can only be resolved by replacing it. To differentiate themselves in the market, each manufacturer incorporates design elements into their weighbridge. Internal structural designs on the market include, among others, I-beams, lighter steel beams, C-channels, bent plates, and steel tubing.

Weighbridge Capacity

The weighbridge design and steel content are excellent indicators of a scale's strength and ability to withstand high traffic volume. Request that your trucking scales distributor demonstrate the benefits and drawbacks of each weighbridge design. In addition, request that your scale distributor provide the steel content of each manufacturer's weighbridge so that you can determine which scale is strong enough for your needs.

Concentrated load capacity (CLC) and dual tandem axle are two industry terms that are frequently used in conjunction with weighbridge capacity and vehicle scale load ratings (DTA). These ratings specify the maximum load that a group of two axles with a center line four feet apart and an axle width eight feet apart can support. A truck scale loaded to CLC/DTA and the displayed weight are recorded during a National Type Evaluation Program (NTEP) test. If the Truck scales falls within acceptable testing tolerances, the CLC/DTA weight is recorded on the scale's Certificate of Conformance.

Examine the Certified truck scales specifications of each manufacturer with your scale distributor and discuss what each specification means for your application. It is important to note that load cell capacities do not directly correlate to scale capacity, and you should always consider the type of loads you will use on your Certified weight scales. A truck scale may require more strength to withstand fewer, heavy loads than an average scale designed for frequent, legal highway loading, depending on your average axle loads. If your application requires Legal for Trade transaction weighments, consult with your truck scales manufacturers or distributor about all scale options, including scales that can provide legal weights in 10 pound increments.

Always discuss your Legal for Trade requirements with your scale distributor and carefully examine each manufacturer's certifications to ensure that your truck scale will meet the requirements of your application. The National Testing and Evaluation Procedure (NTEP) is a set of procedures for the uniform testing and evaluation of weighing equipment. Speak with your vehicle scales for sale distributor for more information on your region's requirements for full scale capacity, CLC/DTA, and NTEP Certification and guidelines, and then choose the best scale to meet those requirements.

Consider Future Capacity.

Ask your scale distributor to show you truck scales with full scale capacities that exceed the weight of a full-size loaded truck you currently use in your operation, and then talk about how much your trucks might weigh in the future if your operations change. With proper care and use, a high-quality truck scales for sale should last 25 years or more. It is critical to ensure that your scale will last through changes in operational capacity before purchasing.

Protection against lightning and transients.

It is critical to protect your vehicle scales from lightning and transient spikes in order to extend its lifespan and reduce electrical component repairs and replacements. Many manufacturers offer packages of lightning and transient protection that include the following features:

  • DC transient protection boards are installed in junction boxes.

  • Copper transient bypass cables are used in load cells.

  • DC transient protection in the indicator's home run cable.

  • Grounding at a single point.

  • From the heavy duty truck scales for sale frame to the AC power ground lug, a bare ground conductor cable is buried in the ground.

  • Before reaching the indicator, ensure that the power supply/surge protector is not interrupted.

  • Warranty on lightning and transient protection.

Proper lightning protection can mean the difference between having to make emergency repairs and continuing with business as usual. Check with your commercial truck scales distributor to see which manufacturers include the aforementioned safety features as standard. Reputable manufacturers and distributors will want to ensure that your truck scale lasts as long as possible, even in the harshest of environments.

Accessories for the system.

Quality truck scale accessories improve efficiency and the flow of trucks into and out of your facility. Knowing which accessories will complement your current operations will allow you to make a more informed decision about the overall truck scale system and manufacturer.

Check your site planning flow chart to see where an accessory can help to speed up processes and reduce the risk of human error. To ensure the best truck maneuverability and flow, always consider the space an accessory will require before installing your truck scale system. Attended and automated ticketing kiosks, remote displays, traffic signals, printers, guiderails, and other accessories are available.

All of these accessories can help truck drivers and construction workers stay safe.

Ticketing kiosks enable drivers to check in, weigh in and out, and print tickets without leaving their truck's cab. Remote displays, gates, and traffic signals can help trucks navigate the weighing process safely and quickly, while guiderails keep trucks on the scale platform.

Truck scale system add-ons.

1. Gates that act as a barrier.

Barrier gates prevent access to your truck scale's entry and exit points. Most gates are electronically controlled to open or close when a specific action is performed.>

2. Kiosks for Automated Ticketing.

pUnattended automated ticketing kiosks optimize truck traffic and improve safety by keeping drivers behind the wheel, from RFID truck identification to load assignment, weighing, and ticketing. Kiosks from many manufacturers can be integrated with your central office and accounting systems.p

3. Stop signs are used to direct traffic.

pStop lights of industrial strength communicate the universal stop/go red and green signals from a distance, accelerating scale traffic and reducing congestion.p

4. Remote Displays.

Remote displays display weight information and direct drivers, increasing efficiency. Displays can be customized to include stop/go red and green signal lights.

5. Printers.

Printers are an excellent way to increase efficiency and accuracy. Printers with connectivity to most digital weight indicators can quickly provide accurate weighment information that is also easy to read.

6. Data Management for Truck Scales.

Truck scale data management software can print tickets or reports and save data to a centralized database. By providing advanced data management and reporting capabilities, data management software improves the functionality of automated ticketing kiosks. 

Most software systems are adaptable to a wide range of industries and are compatible with a wide range of popular operating systems, allowing you to streamline your scale house or front office operations with your truck scale. Most manufacturers' software allows you to generate reports, which are frequently broken down by variables such as customer, hauler, truck, product, and vendor.

What exactly is a load cell?

A load cell, also known as a transducer, is a device that converts mechanical force into an electrical signal. When weight is applied to the load cell, it bends in its most basic form. When a load is applied to a compression-mounted load cell, which is beneath the weighing vessel, such as a truck scale, the load cell compresses. The load cell generates an analog output signal proportional to the weight or force applied. 

The load cell sends this signal to a controller, which converts it to a digital weight measurement. When multiple load cells are required for an application, each load cell should measure the same proportion of total load. In a four-load-cell system, each load cell should measure one-quarter of the total load.

Many load cells are proprietary to a single manufacturer and may necessitate additional maintenance and ownership costs. Discuss all load cell system options with your scale distributor thoroughly.

1. Load cells that are analog.

The strain gauge principle is used by the majority of load cells on the market. Before the load's weight reading can be displayed on an indicator, all load cells must convert their analog values to digital. Some load cells are directly connected to the digital weight indicator, which is where the translation takes place. Other cells on the truck scale installation are linked to summing junction boxes, which sum analog readings from multiple load cells, convert them to digital signals, and send them to the digital weight indicator.

2. Load cells for hydraulics (pressure transmitters).

Hydraulic load cells, unlike most other load cells, do not have strain gauges or internal circuitry. Instead, hydraulic load cells contain hydraulic fluid, and when compressed, a pressure change occurs, which is transmitted via tubing to a summing system, where the pressure is applied to an analog load cell to determine weight.

3. Load cells that convert from analog to digital.

Some analog load cells convert analog to digital signals within the load cell housing. Although the cell is sometimes referred to as a digital load cell, it still measures in analog. In the load cell, converting an analog signal to a digital signal allows the system to compare the output of individual load cells and perform a diagnostic analysis based on that information. Because the conversion occurs in the load cell, the number of sensitive electronic components in the truck scale rentals system increases, making them more vulnerable to damage from vibration, moisture, and increased solder joints.

Load cell classifications.

1. Double-ended Beam Shear.

In North America, this is the most common vehicle semi scales load cell configuration. A compression load cell with a capacity range of 1,000 to 200,000 pounds is a double-ended shear beam load cell. The load applied to the center of the load cell secures the double-ended shear beam at both ends. The strain gauges, as in all shear beam designs, are mounted on a thin web in the cell's machined cavity. The load cell is also less expensive in high capacity applications than the canister load cell because it does not need to be checked, making it a virtually maintenance-free solution.

2. Canister.

The canister load cell is the most traditional type of load cell. These compression devices, which resemble a vertical canister, can handle loads weighing 100 to 1 million pounds. To protect the gauges, it is either hermetically sealed or welded. The drawbacks of this load cell include the need for checking—the installation of check or stay rods to hold the weighbridge in place on the load cell's top plate during weighing.

3. Rocker Column.

Because they are less expensive, some manufacturers prefer rocker column load cells. They do, however, necessitate check rods and bumper bolts, which necessitate maintenance, raising your total cost of ownership. The manufacturer's savings on raw materials are passed on to the end user in the form of additional maintenance.

4. Load Cell Composition

Vehicle weight scales load cells are typically made of stainless steel or steel alloy, but most manufacturers offer a variety of load cell solutions to meet your specific application requirements.

5. Load Cells Made of Tool Alloy Steel.

Load cells made of tool alloy steel elements are by far the most common in use today. When compared to aluminum or stainless steel designs, the cost-to-performance ratio is superior. The most popular alloys are 4330 and 4340 because they have low creep and hysteresis (the change in load cell output over time while under load) (the difference between load cell output readings for the same applied load).

6. Load Cells made of stainless steel.

Stainless steel load cells cost more than tool alloy steel load cells. They may be equipped with hermetically sealed web cavities, making them an excellent choice for corrosive, high-moisture applications. Other than corrosion resistance, stainless steel load cells that are not hermetically sealed have little advantage over comparable cells made of tool alloy steel.